Yes after 30k km my City 1.5 was not able to cross even 120km/ hr and struggle alot to reach even 100km)hr. The i got it cat con opened and there is a thick layer of red mud type dust on face o,f both secondary and primary cats .
Honda Pit shop Gujrat diagnosed the problem and cleaned cat by scraching the thick layer off from both the prim and secondary cat and use air to take out dust. I takes him 1hr to softly scratch and buff. So that no harm is done to the cat con..
Second insident took place with my Ciaz whose cat gets clogged at 40k km .
My Honda Civic Reborn cat con gets clogged at 25k km the cat was bought in 2010 from honda fort and done 25thiusand km in 2018 now with in two years we drove it to 1lack 20thisand